[Bug] Slash commands not intercepted during model response stream

Bug Description
slash commands while the model is responding get sent as followup messages instead of being handled as slash commands

• Attempted to submit feedback about a different issue, while the model was responding
• Instead of triggering the slash command as expected, instead, the text '/feedback' was sent to the model, which is dumb
• Hit #3972 while attempting to submit this bug report (traceback is from that error, afaict)

Error submitting feedback / bug report

Environment Info

• Platform: darwin
• Terminal: tmux
• Version: 1.0.117
• Feedback ID:

Errors

[{"error":"Error: Request was aborted.\n    at new Q5 (unknown:1:28)\n    at new OY (/$bunfs/root/claude:842:1962)\n    at new sQ (/$bunfs/root/claude:842:2748)\n    at _createMessage (/$bunfs/root/claude:850:7955)\n    at processTicksAndRejections (native:7:39)","timestamp":"2025-09-17T17:09:06.416Z"},{"error":"AbortError: The operation was aborted.\n    at unknown\n    at abortChildProcess (node:child_process:859:42)\n    at onAbortListener2 (node:child_process:35:24)\n    at abort (unknown)\n    at <anonymous> (/$bunfs/root/claude:3572:80)","timestamp":"2025-09-17T17:17:15.917Z"},{"error":"Error\n    at lN (/$bunfs/root/claude:536:1076)\n    at z1 (/$bunfs/root/claude:537:9957)\n    at emit (node:events:92:22)\n    at endReadableNT (internal:streams/readable:862:50)\n    at processTicksAndRejections (native:7:39)\n    at request (/$bunfs/root/claude:539:2101)\n    at processTicksAndRejections (native:7:39)","timestamp":"2025-09-17T17:18:00.643Z"}]